The Zhou dynasty 周 (11th cent.-221 BCE) was probably the dynasty that reigned for the longest period of time not only among all Chinese dynasties, but of the whole world. Such a long rule contributed to the image of the Zhou rulers and their political and ritual institutions as examples and guidelines for all later dynasties, at least in theory. The founders of the Zhou dynasty, the kings Wen 周文王 and Wu 周武王 (abbreviated to the couple Wen-Wu 文武), and the Prince Regent, the Duke of Zhou 周公, were seen as ideal monarchs. The Confucians venerated them as moral saints, as arbiters of humanity and righteousness. The Zhou dynasty is one of the Three Dynasties of antiquity (Sandai 三代: Xia 夏, Shang 商 and Zhou).
900 years of history were also characterised by profound changes in society, administration and thought. The first kings of the Zhou enfeoffed their followers and relatives with large domains (fiefs) that after several generations developed to virtually independent states themselves: the central government lost its authority, and the "feudal system" (modern Chinese term fengjian zhidu 封建制度) with its ritual and political obligations disintegrated.
The flight of the Zhou rulers in 770 BCE from their western capital Zongzhou 宗周 (near modern Xi'an 西安, Shaanxi; hence called Western Zhou periodXizhou 西周, 11th cent.-770 BCE) to the eastern capital Chengzhou 成周 (modern Luoyang 洛陽, Henan; hence called Eastern Zhou period, Dongzhou 東周 770-221 BCE) marked the beginning of a new era. The feudal lords (zhuhou 諸侯) competed for power, and some among them took over the position of hegemon (ba 霸), with the duty to protect the royal house of Zhou against the "barbarian" tribes of the north (see Di 狄 and Rong 戎) and to bring order among the various feudal states, and to organise inter-state meetings and alliances (meng 盟).
This age of change, called the "Spring and Autumn period" Chunqiu 春秋 (770-5th cent. BCE), instigated members of the ruling elite to develop new views on society and the universe. The philosophies of Confucianism (see Confucius 孔子) and Daoism emerged. At the same time, politicians tried implementing new forms of administration, in order to strengthen their state. Most prominent among these new politicians was Guan Zhong 管仲.
The political changes inside the feudal states led to a replacement of the ancient feudal dynasties by newcomers and sidelines. In the state of Jin 晉, the houses of Zhao 趙, Han 韓 and Wei 魏, destroyed the ancient dynastic house. In the state of Qi 齊, the noble house of Tian 田 replaced the ancient dynasty, and in the state of Lu 魯, the lateral branches of the ducal house took over the real power. These changes became eminent in the 5th century that marks the beginning of the Warring States periodZhanguo 戰國 (5th cent.-221 BCE). Among the many feudal states that had flourished during the Western and early Eastern Zhou period, only a few survived the belligerent age of the Warring States, and vanished, like Song 宋, Cao 曹 or Chen 陳. At the same time, states in the periphery of the Zhou empire gained prominence and became military powers, like Chu 楚, Wu 吳 and Yue 越 in the south, Qi and Yan 燕 in the east and northeast, and Qin 秦 in the west. The rulers of these states were advised by practial philosophers and strategists. A "hundred schools" of thought (see masters and philosophers) are said to have emerged. The most practical of them were the military strategists (bingjia 兵家), coalition advisors (zonghengjia 縱橫傢), and the legalists (fajia 法家), the latter advocating a more stringent administrative system. The Confucians (rujia 儒家) became more practical and less idealistic with the teachings of Mengzi 孟子 and Xunzi 荀子. The Daoists (daojia 道家) and dialecticians (mingjia 名家) became ever more sceptical about society and state.
The most ruthless and aggressive feudal state was that of Qin in the west. It adopted an effective administrative system and successfully exploited its population for a huge war machine. Qin overcame one by one of the six remaining feudal states, and in 221 BCE the king of Qin, after "unifying the empire" (bing tianxia 並天下) adopted the title of August Emperor (huangdi 皇帝).